【新文速递】2024年10月1日复合材料SCI期刊最新文章

今日更新：Composite Structures 1 篇，Composites Part A: Applied Science and Manufacturing 1 篇Composite StructuresA semi-analytical model for predicting the shear buckling of laminated composite honeycomb cores in sandwich panelsJasotharan Sriharan, Marcelo Dias, Sondipon Adhikari, Dilum Fernandodoi:10.1016/j.compstruct.2024.118629复合材料夹层板蜂窝芯剪切屈曲的半解析模型Laminated composite honeycomb cellular core sandwich panels are widely utilized in various industries due to their exceptional stiffness-to-weight ratio and strength characteristics. Current analytical models often simplify honeycomb cores as homogenized continua, effectively predicting stiffness but falling short in capturing crucial failure modes, particularly shear buckling of honeycomb core walls. Existing theoretical studies on shear buckling are limited to isotropic materials and specific honeycomb geometries. While numerical models can simulate cell wall buckling, their computational demands render them impractical for large structures employing sandwich panels. This paper introduces a novel, simplified semi-analytical approach that accurately predicts the shear buckling load of laminated composite honeycomb cellular cores. The model accounts for bend-twist coupling effects and rotational restraints at laminate wall boundaries. To validate the proposed approach, predictions are compared with finite element analysis results for hexagonal honeycomb cores and cores of varying shapes, incorporating diverse fibre lay-up configurations. The findings demonstrate excellent agreement between the proposed approach and finite element analysis, indicating its reliability in predicting shear buckling. This research addresses the gap in existing methodologies by offering a practical and efficient tool for predicting shear buckling in laminated composite honeycomb cores, extending applicability beyond isotropic materials and specific honeycomb geometries. The proposed approach holds promise for optimizing the design and structural integrity of sandwich panels, impacting industries relying on these lightweight and high-performance structures.层压复合材料蜂窝芯夹芯板以其优异的刚度重量比和强度特性，广泛应用于各行业。目前的分析模型通常将蜂窝芯简化为均质连续体，有效地预测了刚度，但在捕捉关键的破坏模式，特别是蜂窝芯壁的剪切屈曲方面存在不足。现有的剪切屈曲理论研究仅限于各向同性材料和特定的蜂窝几何形状。虽然数值模型可以模拟细胞壁屈曲，但其计算要求使其无法用于采用夹层板的大型结构。本文介绍了一种新的、简化的半解析方法，可以准确地预测层合复合材料蜂窝芯的剪切屈曲载荷。该模型考虑了层合壁边界处的弯扭耦合效应和旋转约束。为了验证所提出的方法，将预测结果与六边形蜂窝芯和不同形状的芯的有限元分析结果进行了比较，其中包含不同的纤维铺设配置。结果表明，该方法与有限元分析结果非常吻合，表明了该方法预测剪切屈曲的可靠性。本研究通过提供一种实用而有效的工具来预测层压复合材料蜂窝芯的剪切屈曲，从而解决了现有方法中的空白，将适用性扩展到各向同性材料和特定蜂窝几何形状之外。所提出的方法有望优化夹层板的设计和结构完整性，影响依赖于这些轻质高性能结构的行业。Composites Part A: Applied Science and ManufacturingFractographic investigation of carbon/epoxy PRSEUS composites exposed to flame after compressive failureDounia Boushab, Aniket Mote, Matthew W. Priddy, Santanu Kundu, Qingsheng Wang, Jaime C. Grunlan, Charles U. Pittman, Thomas E. Lacydoi:10.1016/j.compositesa.2024.108507压缩破坏后碳/环氧复合材料在火焰下的断口形貌研究After a structural-related composite aircraft crash, a fractographic forensic analysis of the damaged surfaces is typically performed to assess the root causes of mechanical failures. Such accident reconstruction efforts, however, can be impeded if the aircraft catches on fire on the ground (i.e., a post-crash fire occurs), where flames or heat exposure can obscure or destroy the fracture surface morphologies of the fibers (i.e., the primary load carrying constituent). In this study, carbon/epoxy Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) skin-stringer assemblies were subjected to uniaxial compression and subsequently exposed to direct flame using a Bunsen burner. Specimens were oriented parallel, orthogonal, and at 45° to the flame axis for durations of 60 s. Additional vertical burn tests were performed for durations up to 300 s. Fractographic inspection of the failure surfaces before and after flame exposure was performed using a combination of destructive sectioning and scanning electron microscopy. The warp-knitted skin (fascia) surrounding the pultruded rod effectively served as a thermal protection layer, which shielded the rod’s broken filaments from significant thermal degradation and facilitated the identification of microbuckling and other mechanical failure mechanisms. This suggests that the presence of fascia, bulkheads, ribs, skins, and other intermediate layers in aircraft structures may significantly shield underlying principal structural element failure surfaces from fire exposure, facilitating post-crash forensic assessments of composite aircraft. Additionally, the through-thickness VectranTM stitching remained intact even after extended flame exposure, suggesting that such stitching can enhance the fire resistance of composite structures.在与结构相关的复合材料飞机坠毁后，通常会对受损表面进行断口学法医分析，以评估机械故障的根本原因。然而，如果飞机在地面着火(即坠机后发生火灾)，这种事故重建工作就会受到阻碍，因为火焰或热暴露会模糊或破坏纤维(即主要承载成分)的断裂表面形态。在这项研究中，碳/环氧拉挤杆缝高效统一结构(PRSEUS)皮肤弦组件进行单轴压缩，随后使用本生灯直接暴露在火焰中。在60 s的时间内，样品与火焰轴平行、正交并呈45°方向。还进行了持续时间长达300 秒的额外垂直燃烧试验。使用破坏性切片和扫描电子显微镜对火焰暴露前后的失效表面进行断口学检查。拉伸杆周围的经编皮肤(筋膜)有效地充当热保护层，保护杆的断裂细丝免受明显的热降解，并有助于识别微屈曲和其他机械失效机制。这表明飞机结构中筋膜、舱壁、肋、表皮和其他中间层的存在可以显著地保护潜在的主要结构元件失效面免受火灾的影响，从而促进复合材料飞机坠毁后的法医评估。此外，即使在长时间的火焰暴露后，通过厚度的VectranTM拼接仍然保持完整，这表明这种拼接可以增强复合材料结构的耐火性。来源：复合材料力学仿真Composites FEM